The application of time domain ground penetrating radar to evaluate railway track ballast

This paper will evaluate Ground Penetrating Radar (GPR) as a Non Destructiv e Test (NDT) technique for the assessment of railway track bed ballast. Bal last and tracked deterioration is responsible for the majority of different ial settlement of tracks, resulting in poor track geometry. Traditionally b allast is only replaced when it has visually deteriorated, resulting in the planning and programming of maintenance and renewals currently being condi tion driven. There is a significant potential cost saving if ballast deteri oration can be detected earlier. GPR can survey large lengths of track ball ast in a relatively short space of time. This paper will show how GPR can b e used to quickly identify the degree of track bed ballast deterioration an d detect the ballast/formation interface. (C) 1999 Published by Elsevier Sc ience Ltd. All rights reserved.